Such sensor elements, which are used, for example, for registering a temperature and are made, for example, of a temperature dependent resistor, are applied in a large number of applications, especially in process automation technology.
Thus, for example, known from German patent application, DE 2251969 A is an apparatus for holding temperature constant, in the case of which a transistor is provided as a heating element along with a diode with temperature dependent properties made of a substance having an abnormal jump in its electrical conductivity.
Furthermore, known from Offenlegungsschrift (laid open German patent application), DE 2300199 A is a powdered substance composed of resistive oxides.
Known from Offenlegungsschrift (laid open German patent application), DE 2424468 A is a temperature compensated, thermorelay system, in the case of which a sudden impedance change occurs at a predetermined transition temperature.
Known from German patent, DE 2436911 B is, furthermore, a method for manufacture of thin-film, hot conductor elements based on vanadium oxide, in the case of which there is applied on a suitable substrate a thin layer, which is composed predominantly of a vanadium oxide material, wherein the vanadium oxide material is, furthermore, doped with foreign atoms.
In principle, it is a problem in temperature measurement to assure that the temperature measurement is reliable and that, for example, no aging related drift-effects occur. Additionally, it is a notorious problem in the case of measuring a temperature to validate, adjust, calibrate and/or certify the measuring transducer, i.e. the so-called temperature sensor element. Especially in process automation technology, such sensor elements, such as, for example, thermometers or, generally, apparatuses for determining temperature, are often integrated in the process in such a manner that their removal is often only possible with great effort or special apparatuses, such as, for example, installation assemblies, which are specially adapted for such purpose. For example, Offenlegungsschrift (laid open German patent application), DE 102010040039 A1 is concerned with the problems arising in the adjusting, calibrating or certification of thermometers.